Kyōko Kanzaki is a supporting character in the series and the biological mother of Mitsuki Kanzaki. Her maiden name is Akesaka. She is a woman who remarries a fellow divorcé, a man with a son named Yūya Kanzaki. Following the marriage, Kyōko and her new husband must relocate overseas due to his job transfer, leaving Mitsuki and Yūya to live alone together. This decision, made without consulting Mitsuki, deeply affects her daughter, who feels abandoned and becomes distant from her new stepbrother. While Kyōko genuinely cares for her daughter and wishes for the new family to function smoothly, her prioritization of the marriage and her husband's career over her daughter's emotional comfort creates a significant rift. Her role in the story is largely that of a catalyst: her departure forces Mitsuki and Yūya into close quarters, a situation that becomes the stage for the supernatural events involving the ghost Hiyori Kotobuki. In terms of personality, Kyōko is presented as a somewhat carefree and perhaps impulsive woman who believes she is acting in everyone's best interest, even if she does not fully grasp the emotional turmoil her daughter is experiencing. Her relationship with Mitsuki is strained due to the perceived abandonment, though it is not irreparably broken; letters or phone calls sometimes bridge the distance, and her presence looms over Mitsuki's internal conflicts about family, trust, and love. Kyōko does not undergo significant development within the course of the main narrative, as her role is primarily offscreen or in the background, serving to establish the premise of the story. She does not possess any supernatural abilities or special skills; her significance lies entirely in her position as the mother who inadvertently sets the central drama into motion through her remarriage and relocation.